I need to build a pad for a 22kW generator I am installing for my house. The image shows the situation. This generator is quite heavy. I plan to pour a rebar reinforced 6" pad for it.

My question is--what to do to fill/retain the area in green? I am guessing this area will be ~18-24" deep at the large end. Because the generator is so heavy, I am tempted to just make the whole thing concrete---but I am afraid doing so will make it tend to slide off of the hill. What is the best approach to ensure that does not happen? Drive rebar into the hill vertically 18" deep 1ft o.c.? or is there an easier/cheaper solution?

sideview of location to install

  • 1
    That location won't be easy or cheap - you need to dig a big hole and install proper support, as Ed's answer details. Though - by the time you've dug the big hole to below frost line, if the space inside the walls is adequate perhaps you just put the generator in the hole on the "slab below frost line" with concrete block walls around it and have a roof that tilts up for access, instead of perching it on top. Might cut the noise down a lot. – Ecnerwal Aug 1 '20 at 0:46
  • @Ecnerwal - answers down there! – FreeMan Aug 1 '20 at 17:07

You will need to dig a footing below the frost level , you don’t want the pad moving around. For diy a easy way to build a concrete wall is with Cinder blocks the hollow concrete blocks you stack like... blocks. Some rebar dropped in them and back fill with concrete can support just about anything including my truck when we brought the generator in. I have even used bagged sackcrete on just such a small retaining wall and I mixed it in a wheelbarrow a fair amount of work but inexpensive and solid. After the footing and wall is cured backfill with dirt or rock. I poured a small pad on top and that powers a remote cabin generator so we had the comforts of home when we went out there.

  • something missing "a pad that powers" – Jasen Aug 1 '20 at 0:11
  • I presume 12" blocks? – peinal Aug 3 '20 at 1:06
  • @jasen I mentioned the pad was strong enough to support my truck when we brought the generator in. Peinal The blocks vary in size your wall being short will probably Be fine with 6” wide I think they are all 8” tall and 16” long. I use 8” wide on taller walls or if cars will be driving next to them where I have made walls to level a driveway their may be shorter I am not sure. – Ed Beal Aug 3 '20 at 13:31
  • I thjink the words are jumbled – Jasen Aug 3 '20 at 19:09

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